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Selective thermal emission and infrared camouflage based on layered media

Chinese Journal of Aeronautics 2023年第3期36卷 212-219页

作者： Qingxiang JI Xueyan CHEN Vincent LAUDE Jun LIANG guodong fang Changguo WANG Rasoul ALAEE Muamer KADIC National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150001China Institute FEMTO-ST CNRSUniversity Bourgogne Franche-Comte´Besanc¸on 25000France Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China Department of Physics University of OttawaOttawaK1N 6N5Canada Institute of Theoretical Solid State Physics Karlsruhe Institute of TechnologyKarlsruhe D-76131Germany

Infrared camouflage based on artificial thermal metasurfaces has recently attracted significant attention.By eliminating thermal radiation differences between the object and the background,it is possible to hide a given object from infrared detection.Infrared camouflage is an important element that increases the survivability of aircraft and missiles,by reducing target susceptibility to infrared guided threats.Herein,a simple and practicable design is theoretically presented based on a multilayer film for infrared stealth,with distinctive advantages of scalability,flexible fabrication,and structural simplicity.The multilayer medium consists of silicon substrate,carbon layer and zinc sulfide film,the optical properties of which are determined by transfer matrix method.By locally changing the thickness of the coating film,the spatial tunability and continuity in thermal emission are demonstrated.A continuous change of emissive power is further obtained and consequently implemented to achieve thermal camouflage functionality.In addition,other functionalities,like thermal illusion and thermal coding,are demonstrated by thickness-engineered multilayer films.

关键词： Heat transfer manipulation Infrared camouflage Multilayer media Selective thermal emission Thermal illusion Transfer matrix method

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Multi-Target Tracking of Person Based on Deep Learning

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Computer Systems Science & Engineering 2023年第11期47卷 2671-2688页

作者： Xujun Li guodong fang Liming Rao Tengze Zhang Physics and Optoelectronic Engineering College Xiangtan UniversityXiangtan411105China

To improve the tracking accuracy of persons in the surveillance video,we proposed an algorithm for multi-target tracking persons based on deep learning.In this paper,we used You Only Look Once v5(YOLOv5)to obtain person targets of each frame in the video and used Simple Online and Realtime Tracking with a Deep Association Metric(DeepSORT)to do cascade matching and Intersection Over Union(IOU)matching of person targets between different frames.To solve the IDSwitch problem caused by the low feature extraction ability of the Re-Identification(ReID)network in the process of cascade matching,we introduced Spatial Relation-aware Global Attention(RGA-S)and Channel Relation-aware Global Attention(RGA-C)attention mechanisms into the network structure.The pre-training weights are loaded for Transfer Learning training on the dataset CUHK03.To enhance the discrimination performance of the network,we proposed a new loss function design method,which introduces the Hard-Negative-Mining way into the benchmark triplet loss.To improve the classification accuracy of the network,we introduced a Label-Smoothing regularization method to the cross-entropy loss.To facilitate the model’s convergence stability and convergence speed at the early training stage and to prevent the model from oscillating around the global optimum due to excessive learning rate at the later stage of training,this paper proposed a learning rate regulation method combining Linear-Warmup and exponential decay.The experimental results on CUHK03 show that the mean Average Precision(mAP)of the improved ReID network is 76.5%.The Top 1 is 42.5%,the Top 5 is 65.4%,and the Top 10 is 74.3%in Cumulative Matching Characteristics(CMC);Compared with the original algorithm,the tracking accuracy of the optimized DeepSORT tracking algorithm is improved by 2.5%,the tracking precision is improved by 3.8%.The number of identity switching is reduced by 25%.The algorithm effectively alleviates the IDSwitch problem,improves the tracking accuracy of persons,and has a high practical v

关键词： YOLOv5 DeepSORT deep learning attention mechanism person re-identification multi-target tracking

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Quantification of the redox properties of microplastics and their effect on arsenite oxidation

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Fundamental Research 2023年第5期3卷 777-785页

作者： Lin Chen Dengjun Wang Tianran Sun Tingting Fan Song Wu guodong fang Min Yang Dongmei Zhou State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China School of Fisheries Aquaculture and Aquatic SciencesAuburn UniversityAuburnAL 36849USA State Key Lab of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Ministry of Environmental Protection of the People’s Republic of China Nanjing Institute of Environmental SciencesNanjing 210008China Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Microplastics have attracted global concern.The environmental-weathering processes control their fate,transport,transformation,and toxicity to wildlife and human health,but their impacts on biogeochemical redox processes remain largely unknown.Herein,multiple spectroscopic and electrochemical approaches in concert with wet-chemistry analyses were employed to characterize the redox properties of weathered microplastics.The spectroscopic results indicated that weathering of phenol-formaldehyde resins(PFs)by hydrogen peroxide(H2O2)led to a slight decrease in the content of phenol functional groups,accompanied by an increase in semiquinone radicals,quinone,and carboxylic groups.Electrochemical and wet-chemistry quantifications,coupled with microbial-chemical characterizations,demonstrated that the PFs exhibited appreciable electron-donating capacity(0.264-1.15 mmol e-g^(-1))and electron-accepting capacity(0.120-0.300 mmol e-g^(-1)).Specifically,the phenol groups and semiquinone radicals were responsible for the electron-donating capacity,whereas the quinone groups dominated the electron-accepting capacity.The reversible redox peaks in the cyclic voltammograms and the enhanced electron-donating capacity after accepting electrons from microbial reduction demonstrated the reversibility of the electron-donating and-accepting reactions.More importantly,the electron-donating phenol groups and weathering-induced semiquinone radicals were found to mediate the production of H2O2 from oxygen for arsenite oxidation.In addition to the H2O2-weathered PFs,the ozone-aged PF and polystyrene were also found to have electron-donating and arsenite-oxidation capacity.This study reports important redox properties of microplastics and their effect in mediating contaminant transformation.These findings will help to better understand the fate,transformation,and biogeochemical roles of microplastics on element cycling and contaminant fate.

关键词： Microplastics Weathering Redox property Semiquinone radicals Electron-donating and-accepting capacity Arsenite oxidation

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Effects of iron(hydr)oxides on the degradation of diethyl phthalate ester in heterogeneous(photo)-Fenton reactions

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Journal of Environmental Sciences 2019年第6期31卷 5-13页

作者： Wenjuan Shuai Cheng Gu guodong fang Dongmei Zhou Juan Gao Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science Chinese Academy of Science University of Chinese Academy of Sciences State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University

This work studied the structural effects of hematite(α-Fe2 O3), 2-line ferrihydrite(HFO) and goethite(α-FeOOH) on diethyl phthalate ester(DEP) degradation. The results showed that the degradation of DEP was faster under 365 nm light irradiation than in the dark in the presence of iron(hydr)oxides. The apparent kinetic rates of DEP degradation followed the order HFO > goethite ≈ hematite in the dark and HFO > hematite > goethite under 365 nm light irradiation. Two pathways governed H2 O2 decomposition efficiency on iron(hydr)oxide surfaces:(1) forming UOH on inherent surface hydroxyl groups(Fe-OH) and(2) producing O2 and H2 O on the surface oxygen vacancies. X-ray photoelectron spectroscopy(XPS) analyses indicated that HFO not only has high Fe-OH content but also has high Vo content, resulting in its low H2 O2 utilization efficiency(η). DEP was degraded through hydrogen abstraction and deesterification, and the major products were(OH)2-DEP, mono-ethyl phthalate(MEP), OH-MEP,and phthalate acid(PA). The study is important in understanding the transformation of phthalate esters in top surface soils and surface waters under ultraviolet light.

关键词： Diethyl phthalate ester Iron(hydr)oxide Hydroxyl radical Heterogeneous Fenton reactions

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Nano Fe_(2)O_(3)embedded in montmorillonite with citric acid enhanced photocatalytic activity of nanoparticles towards diethyl phthalate

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Journal of Environmental Sciences 2021年第3期33卷 248-259页

作者： Zhaoyue Sun Lisha Feng guodong fang Longgang Chu Dongmei Zhou Juan Gao Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science Chinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China

Nano-Fe_(2)O_(3)embedded in montmorillonite particles(Fe-Mt)were prepared to degrade diethyl phthalate(DEP)with citric acid(CA)under xenon light irradiation.Compared to pristine montmorillonite(Na-Mt),the embedding process increased 14.5-fold of iron content and 1.8-fold of specific surface area.The synthesized Fe-Mt have more oxygen vacancies than Fe_(2)O_(3)nanoparticles(nFe_(2)O_(3)),which could induce more reactive oxygen species(ROSs)generation in the presence of CA under xenon lamp irradiation.Fe-Mt with CA enhanced photo-assisted degradation of DEP 2.5 times as compared to nFe_(2)O_(3)with CA.Quenching experiments,electron paramagnetic resonance(EPR)spectroscopy and identification of products confirmed that surface-bound·OH was the main radical to degrade DEP.Common anions(i.e.,NO_(3)-,CO_(3)^(2-),Cl^-)and humic acid could compete·OH with DEP and cause slower degradation of DEP.The removal efficiency of DEP was more than 56%with Fe-Mt after three recycles,and the dissolved Fe concentration from Fe-Mt was below 75μmol/L,indicating Fe-Mt had a good stability as a catalyst.Fe-Mt together with CA appeared to be a promising strategy to remove organic pollutants in surface water,or topsoil under solar irradiation.

关键词： Heterogeneous catalyst Hydroxyl radical Photo-Fenton reactions Phthalate ester

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Biochar-supported nano-scale zerovalent iron activated persulfate for remediation of aromatic hydrocarbon-contaminated soil:an in-situ pilot-scale study

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Biochar 2022年第1期4卷 122-133页

作者： Yu Zeng Tai Li Yingzhi Ding guodong fang Xiaolei Wang Bo Ye Liqiang Ge Juan Gao Yujun Wang Dongmei Zhou Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China School of Environmental and Safety Engineering Changzhou UniversityChangzhou 213164China School of Earth and Environment Anhui University of Science and TechnologyHuainan 232001People’s Republic of China Geological Survey of Jiangsu Province Nanjing 210018People’s Republic of China State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023People’s Republic of China

Biochar supported nano-scale zerovalent iron(nZVI/BC)for persulfate(PS)activation has been studied extensively for the degradation of pollutants on the lab scale,but it was rarely applied in practical soil remediation in the field.In this research,we developed a facile ball-milling method for the mass production of nZVI/BC,which was successfully applied to activate persulfate for the remediation of organic polluted soil on an in-situ pilot scale.In-situ high-pressure injection device was developed to inject nZVI/BC suspension and PS solution into the soil with a depth of 0-70 cm.The removal efficiency of target pollutants such as 2-ethylnitrobenzene(ENB,1.47-1.56 mg/kg),biphenyl(BP,0.19-0.21 mg/kg),4-(methylsulfonyl)toluene(MST,0.32-0.43 mg/kg),and 4-phenylphenol(PP,1.70-2.46 mg/kg)at different soil depths was 99.7%,99.1%,99.9%and 99.7%,respectively,after 360 days of remediation.The application of nZVI/BC significantly increased the degradation rates of contaminants by 11-322%,ascribed to its relatively higher efficiency of free radical generation than that of control groups.In addition,it was found that nZVI/BC-PS inhibited soil urease and sucrase enzyme activities by 1-61%within 55 days due to the oxidative stress for microbes induced by free radicals,while these inhibition effects disappeared with remediation time prolonged(>127 days).Our research provides a useful implementation case of remediation with nZVI/BC-PS activation and verifies its feasibility in practical contaminated soil remediation.

关键词： Persulfate Biochar Nanoscale zerovalent iron Pilot-scale Enzyme activities

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Achieving thermal magnification by using effective thermal conductivity

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Theoretical & Applied Mechanics Letters 2018年第3期8卷 164-170页

作者： Qingxiang Ji guodong fang Jun Liang Center for Composite Materials Harbin Institute of Technology Institute of Advanced Structure Technology Beijing Institute of Technology

thermal magnification device is proposed by using effective thermal conductivity. Different fromtransformation optics method, the magnification design is realized analytically by enforcingequality of effective thermal conductivity on the magnification device and the reference case inspecified domains. The validity of theoretical analysis is checked by numerical simulation results,which demonstrates the magnifying effects of the proposed design. The device only needsisotropic and homogeneous materials that are easy to obtain in nature. It is also shown that theobtained magnifying conditions are the same as those derived by separation of variables. But theproposed method proves more flexible for multilayered materials and simpler for non-sphericalobjects under non-uniform thermal fields. It can also be extended to other fields and applicationsgoverned by Laplace equation.

关键词： Thermal magnification Effective thermal conductivity Separation of variables

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节能降耗视角下石油化工工艺技术性安全策略分析

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当代化工研究 2024年第4期 145-147页

作者：房国栋刘书玉山东宏旭化学股份有限公司山东257500

石油化工行业在进行生产工作时,需要应用到多项复杂技术,并且其中存在的隐患问题比较多,如果没有及时发现隐患,所造成的安全事故会严重威胁到企业的正常发展以及现场工作人员的人身安全。所以在节能降耗视角下,针对石油化工工艺技术安... 详细信息

石油化工行业在进行生产工作时,需要应用到多项复杂技术,并且其中存在的隐患问题比较多,如果没有及时发现隐患,所造成的安全事故会严重威胁到企业的正常发展以及现场工作人员的人身安全。所以在节能降耗视角下,针对石油化工工艺技术安全开展研究是非常必要的事情。对此本文通过分析石油化工工艺流程中技术性安全问题,并基于节能降耗的视角下提出石油化工生产技术安全的控制策略,希望能够为石油化工行业的工作人员在开展工作方面提供参考。

关键词：节能降耗石油化工工艺技术性安全策略

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纳米MgO对聚苯乙烯基相变复合纤维形貌及热学性能的影响

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化工新型材料 2024年第6期52卷 113-116,121页

作者：方国栋柯惠珍李浩浩张伊龙颉海娟常迎迎新疆大学纺织与服装学院乌鲁木齐830046 闽江学院服装与艺术工程学院福建省新型功能性纺织纤维及材料重点实验室福州350108

采用静电纺丝法制备负载不同含量纳米氧化镁(MgO)的聚苯乙烯(PS)基复合纤维膜作为支撑材料,以癸酸-月桂酸-棕榈酸(CLP)三元低共熔物为固-液相变储能材料,通过物理吸附法制备CLP/PS/MgO相变复合纤维膜,研究了纳米MgO含量对相变复合纤维... 详细信息

采用静电纺丝法制备负载不同含量纳米氧化镁(MgO)的聚苯乙烯(PS)基复合纤维膜作为支撑材料,以癸酸-月桂酸-棕榈酸(CLP)三元低共熔物为固-液相变储能材料,通过物理吸附法制备CLP/PS/MgO相变复合纤维膜,研究了纳米MgO含量对相变复合纤维膜形貌结构、储热性能以及热稳定性的影响。结果表明:静电纺PS/MgO复合纤维膜呈现三维网络结构特征,纤维呈圆柱形且表面光滑,表明纳米MgO与PS相容性良好,随着纳米MgO含量的增加,纤维的平均直径呈先增大后减小的趋势,纤维平均直径在1.35~1.82μm之间,CLP三元低共熔物可以很好地封装在复合纤维膜中。热稳定性能分析结果表明CLP/PS/MgO相变复合纤维膜的熔化温度约为20℃,结晶温度约为10℃,相变焓为106~124kJ/kg,适用于储能调温纺织品以及建筑节能领域。纳米MgO的加入对相变复合纤维的相变温度没有显著影响,相变焓略微下降,热稳定性明显提高。

关键词：纳米氧化镁聚苯乙烯相变纤维膜储热性能热稳定性

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稻田上覆水中光致活性组分形成过程及其环境效应研究进展

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土壤学报 2024年第4期61卷 929-938页

作者：曾宇张明洋李马波陈宁方国东高娟王玉军周东美中国科学院土壤环境与污染修复重点实验室中国科学院南京土壤研究所南京210008 中国科学院大学北京100049 南京大学环境学院南京210023

稻田上覆水中富含有机质、亚硝酸盐和硝酸盐等光敏活性物质,在太阳光作用下会产生三重激发态有机质(3CDOM*)、单线态氧(1O_(2))和羟基自由基(•OH)等活性组分,其对稻田污染物转化和碳氮等元素循环具有重要意义。基于此,综述了稻田上覆水... 详细信息

稻田上覆水中富含有机质、亚硝酸盐和硝酸盐等光敏活性物质,在太阳光作用下会产生三重激发态有机质(3CDOM*)、单线态氧(1O_(2))和羟基自由基(•OH)等活性组分,其对稻田污染物转化和碳氮等元素循环具有重要意义。基于此,综述了稻田上覆水中光致活性组分产生过程和机制,重点介绍了水稻不同生长周期内光活性组分的类型、通量变化趋势;探讨了不同环境因素对自由基产生的影响;阐述了上覆水光致活性组分对稻田中砷和不同有机污染物的非生物转化贡献与机制,并展望了稻田上覆水光化学过程的未来研究方向。

关键词：稻田上覆水光化学活性中间体有机质污染物降解

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